--[[
This module is intended to provide access to basic string functions.
Most of the functions provided here can be invoked with named parameters,
unnamed parameters, or a mixture. If named parameters are used, Mediawiki will
automatically remove any leading or trailing whitespace from the parameter.
Depending on the intended use, it may be advantageous to either preserve or
remove such whitespace.
Global options
ignore_errors: If set to 'true' or 1, any error condition will result in
an empty string being returned rather than an error message.
error_category: If an error occurs, specifies the name of a category to
include with the error message. The default category is
[Category:Errors reported by Module String].
no_category: If set to 'true' or 1, no category will be added if an error
is generated.
Unit tests for this module are available at Module:String/tests.
]]
local p = {}
--[[
Helper function that populates the argument list given that user may need to use a mix of
named and unnamed parameters. This is relevant because named parameters are not
identical to unnamed parameters due to string trimming, and when dealing with strings
we sometimes want to either preserve or remove that whitespace depending on the application.
]]
local function _getParameters( frame_args, arg_list )
local new_args = {}
local index = 1
local value
for _, arg in ipairs( arg_list ) do
value = frame_args[arg]
if value == nil then
value = frame_args[index]
index = index + 1
end
new_args[arg] = value
end
return new_args
end
--[[
Helper Function to interpret boolean strings
]]
local function _getBoolean( boolean_str )
local boolean_value
if type( boolean_str ) == 'string' then
boolean_str = boolean_str:lower()
if boolean_str == 'false' or boolean_str == 'no' or boolean_str == '0'
or boolean_str == '' then
boolean_value = false
else
boolean_value = true
end
elseif type( boolean_str ) == 'boolean' then
boolean_value = boolean_str
else
error( 'Cap valor booleà trobat' )
end
return boolean_value
end
--[[
Helper function to handle error messages.
]]
local function _error( error_str )
local frame = mw.getCurrentFrame()
local error_category = frame.args.error_category or 'Errors detectats pel mòdul String'
local ignore_errors = frame.args.ignore_errors or false
local no_category = frame.args.no_category or false
if _getBoolean(ignore_errors) then
return ''
end
local error_str = '<strong class="error">Error del mòdul String: ' .. error_str .. '</strong>'
if error_category ~= '' and not _getBoolean( no_category ) then
error_str = '[[Category:' .. error_category .. ']]' .. error_str
end
return error_str
end
--[[
Helper function that escapes all pattern characters so that they will be treated
as plain text.
]]
local function _escapePattern( pattern_str )
return mw.ustring.gsub( pattern_str, "([%(%)%.%%%+%-%*%?%[%^%$%]])", "%%%1" )
end
--[[
len
This function returns the length of the target string.
Usage:
{{#invoke:String|len|target_string|}}
OR
{{#invoke:String|len|s=target_string}}
Parameters
s: The string whose length to report
If invoked using named parameters, Mediawiki will automatically remove any leading or
trailing whitespace from the target string.
]]
function p.len( frame )
local new_args = _getParameters( frame.args, {'s'} )
local s = new_args['s'] or ''
return mw.ustring.len( s )
end
--[[
sub
This function returns a substring of the target string at specified indices.
Usage:
{{#invoke:String|sub|target_string|start_index|end_index}}
OR
{{#invoke:String|sub|s=target_string|i=start_index|j=end_index}}
Parameters
s: The string to return a subset of
i: The fist index of the substring to return, defaults to 1.
j: The last index of the string to return, defaults to the last character.
The first character of the string is assigned an index of 1. If either i or j
is a negative value, it is interpreted the same as selecting a character by
counting from the end of the string. Hence, a value of -1 is the same as
selecting the last character of the string.
If the requested indices are out of range for the given string, an error is
reported.
]]
function p.sub( frame )
local new_args = _getParameters( frame.args, { 's', 'i', 'j' } )
local s = new_args['s'] or ''
local i = tonumber( new_args['i'] ) or 1
local j = tonumber( new_args['j'] ) or -1
local len = mw.ustring.len( s )
-- Convert negatives for range checking
if i < 0 then
i = len + i + 1
end
if j < 0 then
j = len + j + 1
end
if i > len or j > len or i < 1 or j < 1 then
return _error( 'Índex fora del rang de la cadena' )
end
if j < i then
return _error( 'Índexs de la cadena no ordenats' )
end
return mw.ustring.sub( s, i, j )
end
--[[
match
This function returns a substring from the source string that matches a
specified pattern.
Usage:
{{#invoke:String|match|source_string|pattern_string|start_index|match_number|plain_flag|nomatch_output}}
OR
{{#invoke:String|match|s=source_string|pattern=pattern_string|start=start_index
|match=match_number|plain=plain_flag|nomatch=nomatch_output}}
Parameters
s: The string to search
pattern: The pattern or string to find within the string
start: The index within the source string to start the search. The first
character of the string has index 1. Defaults to 1.
match: In some cases it may be possible to make multiple matches on a single
string. This specifies which match to return, where the first match is
match= 1. If a negative number is specified then a match is returned
counting from the last match. Hence match = -1 is the same as requesting
the last match. Defaults to 1.
plain: A flag indicating that the pattern should be understood as plain
text. Defaults to false.
nomatch: If no match is found, output the "nomatch" value rather than an error.
If invoked using named parameters, Mediawiki will automatically remove any leading or
trailing whitespace from each string. In some circumstances this is desirable, in
other cases one may want to preserve the whitespace.
If the match_number or start_index are out of range for the string being queried, then
this function generates an error. An error is also generated if no match is found.
If one adds the parameter ignore_errors=true, then the error will be suppressed and
an empty string will be returned on any failure.
For information on constructing Lua patterns, a form of [regular expression], see:
* http://www.lua.org/manual/5.1/manual.html#5.4.1
* http://www.mediawiki.org/wiki/Extension:Scribunto/Lua_reference_manual#Patterns
* http://www.mediawiki.org/wiki/Extension:Scribunto/Lua_reference_manual#Ustring_patterns
]]
-- This sub-routine is exported for use in other modules
function p._match( s, pattern, start, match_index, plain_flag, nomatch )
if s == '' then
return _error( 'Cadena on cercar està buida' )
end
if pattern == '' then
return _error( 'Cadena de cerca està buida' )
end
start = tonumber(start) or 1
if math.abs(start) < 1 or math.abs(start) > mw.ustring.len( s ) then
return _error( 'Índex d\'inici fora del rang de la cadena' )
end
if match_index == 0 then
return _error( 'Número de coincidència fora de rang' )
end
if plain_flag then
pattern = str._escapePattern( pattern )
end
local result
if match_index == 1 then
-- Find first match is simple case
result = mw.ustring.match( s, pattern, start )
else
if start > 1 then
s = mw.ustring.sub( s, start )
end
local iterator = mw.ustring.gmatch(s, pattern)
if match_index > 0 then
-- Forward search
for w in iterator do
match_index = match_index - 1
if match_index == 0 then
result = w
break
end
end
else
-- Reverse search
local result_table = {}
local count = 1
for w in iterator do
result_table[count] = w
count = count + 1
end
result = result_table[ count + match_index ]
end
end
if result == nil then
if nomatch == nil then
return _error( 'Cap coincidència trobada' )
else
return nomatch
end
else
return result
end
end
-- This is the entry point for #invoke:String|match
function p.match( frame )
local new_args = _getParameters( frame.args, {'s', 'pattern', 'start', 'match', 'plain', 'nomatch'} )
local s = new_args['s'] or ''
local start = tonumber( new_args['start'] ) or 1
local plain_flag = _getBoolean( new_args['plain'] or false )
local pattern = new_args['pattern'] or ''
local match_index = math.floor( tonumber(new_args['match']) or 1 )
local nomatch = new_args['nomatch']
return p._match( s, pattern, start, match_index, plain_flag, nomatch )
end
--[[
pos
This function returns a single character from the target string at position pos.
Usage:
{{#invoke:String|pos|target_string|index_value}}
OR
{{#invoke:String|pos|target=target_string|pos=index_value}}
Parameters
target: The string to search
pos: The index for the character to return
If invoked using named parameters, Mediawiki will automatically remove any leading or
trailing whitespace from the target string. In some circumstances this is desirable, in
other cases one may want to preserve the whitespace.
The first character has an index value of 1.
If one requests a negative value, this function will select a character by counting backwards
from the end of the string. In other words pos = -1 is the same as asking for the last character.
A requested value of zero, or a value greater than the length of the string returns an error.
]]
function p.pos( frame )
local new_args = _getParameters( frame.args, {'target', 'pos'} )
local target_str = new_args['target'] or ''
local pos = tonumber( new_args['pos'] ) or 0
if pos == 0 or math.abs(pos) > mw.ustring.len( target_str ) then
return _error( 'Índex fora del rang de la cadena' )
end
return mw.ustring.sub( target_str, pos, pos )
end
--[[
find
This function allows one to search for a target string or pattern within another
string.
Usage:
{{#invoke:String|find|source_str|target_string|start_index|plain_flag}}
OR
{{#invoke:String|find|source=source_str|target=target_str|start=start_index|plain=plain_flag}}
Parameters
source: The string to search
target: The string or pattern to find within source
start: The index within the source string to start the search, defaults to 1
plain: Boolean flag indicating that target should be understood as plain
text and not as a Lua style regular expression, defaults to true
If invoked using named parameters, Mediawiki will automatically remove any leading or
trailing whitespace from the parameter. In some circumstances this is desirable, in
other cases one may want to preserve the whitespace.
This function returns the first index >= "start" where "target" can be found
within "source". Indices are 1-based. If "target" is not found, then this
function returns 0. If either "source" or "target" are missing / empty, this
function also returns 0.
This function should be safe for UTF-8 strings.
]]
function p.find( frame )
local new_args = _getParameters( frame.args, {'source', 'target', 'start', 'plain' } )
local source_str = new_args['source'] or ''
local pattern = new_args['target'] or ''
local start_pos = tonumber(new_args['start']) or 1
local plain = new_args['plain'] or true
if source_str == '' or pattern == '' then
return 0
end
plain = _getBoolean( plain )
local start = mw.ustring.find( source_str, pattern, start_pos, plain )
if start == nil then
start = 0
end
return start
end
--[[
replace
This function allows one to replace a target string or pattern within another
string.
Usage:
{{#invoke:String|replace|source_str|pattern_string|replace_string|replacement_count|plain_flag}}
OR
{{#invoke:String|replace|source=source_string|pattern=pattern_string|replace=replace_string|
count=replacement_count|plain=plain_flag}}
Parameters
source: The string to search
pattern: The string or pattern to find within source
replace: The replacement text
count: The number of occurences to replace, defaults to all.
plain: Boolean flag indicating that pattern should be understood as plain
text and not as a Lua style regular expression, defaults to true
]]
function p.replace( frame )
local new_args = _getParameters( frame.args, {'source', 'pattern', 'replace', 'count', 'plain' } )
local source_str = new_args['source'] or ''
local pattern = new_args['pattern'] or ''
local replace = new_args['replace'] or ''
local count = tonumber( new_args['count'] )
local plain = new_args['plain'] or true
if source_str == '' or pattern == '' then
return source_str
end
plain = _getBoolean( plain )
if plain then
pattern = _escapePattern( pattern )
replace = mw.ustring.gsub( replace, "%%", "%%%%" ) --Only need to escape replacement sequences.
end
local result
if count ~= nil then
result = mw.ustring.gsub( source_str, pattern, replace, count )
else
result = mw.ustring.gsub( source_str, pattern, replace )
end
return result
end
--[[
simple function to pipe string.rep to templates.
]]
function p.rep( frame )
local repetitions = tonumber( frame.args[2] )
if not repetitions then
return _error( "s'esperava un número com a segon paràmetre; trobat: " .. ( frame.args[2] or '' ))
end
return string.rep( frame.args[1] or '', repetitions )
end
--[[
escapePattern
This function escapes special characters from a Lua string pattern. See [1]
for details on how patterns work.
[1] https://www.mediawiki.org/wiki/Extension:Scribunto/Lua_reference_manual#Patterns
Usage:
{{#invoke:String|escapePattern|pattern_string}}
Parameters
pattern_string: The pattern string to escape.
]]
function p.escapePattern( frame )
local pattern_str = frame.args[1]
if not pattern_str then
return _error( 'No pattern string specified' )
end
local result = _escapePattern( pattern_str )
return result
end
--[[
count
This function counts the number of occurrences of one string in another.
]]
function p.count(frame)
local args = _getParameters(frame.args, {'source', 'pattern', 'plain'})
local source = args.source or ''
local pattern = args.pattern or ''
local plain = _getBoolean(args.plain or true)
if plain then
pattern = _escapePattern(pattern)
end
local _, count = mw.ustring.gsub(source, pattern, '')
return count
end
--[[
endswith
This function determines whether a string ends with another string.
]]
function p.endswith(frame)
local args = _getParameters(frame.args, {'source', 'pattern'})
local source = args.source or ''
local pattern = args.pattern or ''
if pattern == '' then
-- All strings end with the empty string.
return "yes"
end
if mw.ustring.sub(source, -mw.ustring.len(pattern), -1) == pattern then
return "yes"
else
return ""
end
end
--[[
join
Join all non empty arguments together; the first argument is the separator.
Usage:
{{#invoke:String|join|sep|one|two|three}}
]]
function p.join(frame)
local args = {}
local sep
for _, v in ipairs( frame.args ) do
if sep then
if v ~= '' then
table.insert(args, v)
end
else
sep = v
end
end
return table.concat( args, sep or '' )
end
--[[
Strip
This function Strips charecters from string
Usage:
{{#invoke:StringFunc|strip|source_string|charecters_to_strip|plain_flag}}
Parameters
source: The string to strip
chars: The pattern or list of charecters to strip from string, replaced with ''
plain: A flag indicating that the chars should be understood as plain text. defaults to true.
Leading and trailing whitespace is also automatically stripped from the string.
]]
function p.strip( frame )
local new_args = _getParameters( frame.args, {'source', 'chars', 'plain'} )
local source_str = new_args['source'] or ''
local chars = new_args['chars'] or ''
source_str = mw.text.trim(source_str)
if source_str == '' or chars == '' then
return source_str
end
local l_plain = _getBoolean( new_args['plain'] or true )
if l_plain then
chars = _escapePattern( chars )
end
local result
result = mw.ustring.gsub(source_str, "["..chars.."]", '')
return result
end
--[[
Split
This function Splits a string based on a separator, returns nth substring based on count.
Usage:
{{#invoke:StringFunc|split|source_string|separator|count}}
Parameters:
source: The string to return a subset of
separator: The string to split on
count: The nth substring based on the separator to return
]]
function p.split( frame )
local new_args = _getParameters( frame.args, {'source', 'separator', 'count'} )
local source_str = new_args['source'] or ''
local separator = (new_args['separator'] or ''):gsub('"', '')
local separator_len = mw.ustring.len(separator)
if source_str == '' or separator == '' then
return source_str;
end
local ret_count = tonumber( new_args['count'] ) or 1
if ret_count < 1 then
return ""
end
local start = 1
local iter = mw.ustring.find(source_str, separator, start, true)
if iter == nil then
if ret_count == 1 then
return source_str
else
return ""
end
else
iter = iter - 1
end
if ret_count == 1 then
return mw.ustring.sub( source_str, start, iter)
end
for i=2, ret_count do
start = iter+separator_len + 1
iter = mw.ustring.find(source_str, separator, start, true)
if iter == nil then
if ret_count == i then
return mw.ustring.sub(source_str, start, mw.ustring.len(source_str))
else
return ""
end
else
iter = iter - 1
end
end
return mw.ustring.sub( source_str,start,iter)
end
function p.isNumber( frame )
local new_args = _getParameters( frame.args, {'source'} )
local source_str = new_args['source'] or ''
if source_str == '' then
return "false"
end
if tonumber(source_str) == nil and tonumber(string.gsub(source_str, ",", ".", 1) .. '') == nil then
return "false"
end
return "true"
end
return p
